The present invention is directed to image-processing systems, particularly those in which updated image values are generated as functions both of previous values and of new data.
In many image-processing systems, the raw data must be subjected to various types of transformations. Some of the transformations depend only on the values of the current input signals. For instance, some image processing involves so-called gamma correction, which compensates for the non-linear relationship between a camera output and the intensities to which the camera responds. Other forms of transformation depend not only on the data currently being obtained but also on the data previously stored. For instance, systems for detecting changes in an image may subtract current pixel (picture-element) values from stored pixel values to detect movement in the image. Another example of processing that uses both stored data and newly generated data is noise reduction by averaging over a plurality of successive scans of an image. These separate functions are commonly provided by separate specialized circuits or by generalized arithmetic logic units. Both of these approaches can be relatively expensive, and the time that it takes a generalized arithmetic logic unit to perform certain real-time applications may be prohibitive.
An object of the present invention is to provide a variety of image-processing features in fast and relatively simple and inexpensive circuitry.